thanks for joining me at underwater math today we're going to review three-digit edition with regrouping you might see an addition problem written out horizontally like this or you might see it written vertically like this either way when you start working the problem the most important thing to remember is to line up the place values in the numbers you are adding what exactly do you mean by lining up the place values good question i like to stack the numbers i'm adding on top of each other then i make sure the ones place on the top number is right above the ones place in the bottom number next i make sure the tenths place of the top number is right above the tenths place of the bottom number finally i make sure the hundreds place of the top number is right above the hundredths place of the bottom number now i can start to add always remember to start at the smallest place value all the way to the right that would be the ones place let's make sure we line up the place values then we can start with adding in the ones place what is seven plus five it's twelve but i'm not sure how to put two digits underneath the ones place how can i put twelve ones down i'm pretty sure fifty twelve is not a real number well unfortunately you can't but we can do something called carrying over or regrouping we need to rewrite those twelve ones as one ten and two ones then we can regroup so let's place that 110 above the tens place stack and we will place the two below the ones place stack i think i get it now let me try adding the tens since we carried over that one now there are three numbers to add in the stack one plus six plus nine equals sixteen and then we can rewrite sixteen just like we did before sixteen tens equals one hundred and six tens so place that one hundred above the hundreds place stack and place the six below the tens place stack excellent now we just have the hundreds place to add again there are three numbers to add in this stack one plus four plus two equals seven we'll just write the seven below the hundredths place and then voila we have our sum 762. that's not so difficult thanks for helping me out no problem you did great work today this was a fun ad venture i can't wait to do more math soon